The TRUTH Behind INTERMITTENT FASTING (Doctor’s Opinion) | Fat Loss, Muscle Growth, Health Benefits

The TRUTH Behind INTERMITTENT FASTING (Doctor’s Opinion) | Fat Loss, Muscle Growth, Health Benefits

Yo what’s up?! Dr. Swole here, MD bodybuilder back with another video today we’re gonna be talking about
intermittent fasting as a side note I’ve been getting a lot of feedback about the
audio on my videos so I got a new microphone we’ll see how it does
intermittent fasting is the practice of restricting your calories over certain
regular time intervals this has been gaining a lot of popularity over the
last few years and I’ve been getting a lot of questions about it today we’re
gonna try and clear up some of the misconceptions around intermittent
fasting my main area of expertise is in body composition for bodybuilding so
we’re gonna focus on intermittent fasting application for body composition
we’ll talk about some of the pros and cons of implementing intermittent
fasting I’ve been getting asked a lot for my thoughts on whether there are
actual health benefits related to intermittent fasting we’ll touch on
those that is not my area of expertise but I’ll just address it and give my
personal opinion lastly if you do choose to implement it your in fasting
we’ll talk briefly about how to do it first of all we’re going to talk about
intermittent fasting for body composition in other words building
muscle and losing fat now a lot of people talk about intermittent fasting
as a better way to lose weight I’m gonna say up front that intermittent fasting
doesn’t give you any magical benefit for a fat loss ultimately what determines
whether you lose weight or not is your caloric deficit so calories in versus
calories out and on the flip side for building muscle there is a possible
detriment of intermittent fasting which we’ll talk about further in a minute
based on the data we have right now I’d say that if you choose to do
intermittent fasting or not it’s largely up to personal preference I’m gonna lay
out some of the pros and cons of intermittent fasting so you can better
make your decision all right so let’s talk about the pros of interent fasting
as a brief aside the main ways that intermittent fasting has been
implemented in the literature is either to do a shortened time window for which
you’re eating throughout the day like fasting for 16 hours and eating for 8
hours and then there is a 5 and 2 method where
you might eat normally for 5 days of the week and fast for 2 days and there have
also been studies on alternate day fasting so one day eating normally one
day fasting now when I say fasting for the
sixteen and eight method for example people usually do not eat anything at
all during those fasting hours but for the five and to an alternate day fasting
it usually means just a drastic restriction in calories now I think the
biggest reason why you might choose to do intermittent fasting especially for
fat loss is because you tend to eat less if you’re spending fewer hours eating
you’ve probably noticed this happen on days when say you sleep in really late
and you end up skipping breakfast often you don’t end up actually making up that
meal later and you end up consuming less overall throughout the day this I think
is the main reason why intermittent fasting can work for some people
essentially whatever helps you enact that calorie deficit is a good thing and
will help you lose fat over time now the next advantage of intermittent fasting is
simply that it can be more convenient for some people just the fact that
you’re able to say skip breakfast or dinner might fit better into people’s
schedules last of all anecdotally some people
report cognitive benefits with intermittent fasting of course you’ll
have to try this out to see if it’s something that happens for you okay so
now let’s move on to talk about some of the cons of interment fasting first of
all intermittent fasting comes with an adjustment period when you first switch
over to this new schedule of eating you’re going to feel really hungry at
the times you’re fasting most people find that this adjustment period lasts
for about a month next intermittent fasting requires
long-term adherence people might hear intermittent fasting and say oh so if i skip
breakfast once in a while it’s okay however there’s actually research
showing that people who have a very irregular eating pattern end up having
poor metabolic outcomes metabolic outcomes usually refers to things like
weight blood pressure or other factors that can affect your heart health
another con of intermittent fasting on the flip side of it being convenient is that
it can interfere with people’s social life this is largely a product of the
way our modern culture is set up where a lot of our social activities were
revolve around food lastly intermittent fasting can make it difficult for you to
consume enough calories when you’re bulking this is basically just the
opposite of its advantage for fat loss
related to this there’s also a theoretical disadvantage for restricting the hours
in which you’re consuming protein now after you consume a meal containing
protein your body has an anabolic response that follows a u-shaped curve
now what that means is that the protein you consume only can spike muscle growth
for a certain amount of time before it levels off and eventually you might turn
towards a more catabolic state so it makes sense that if you’re restricting
your eating to only a few hours a day you might be disadvantaging yourself
from a muscle synthesis standpoint however this is somewhat offset by the
fact that if you consume larger amounts of food or more complex foods such as
those containing a lot of fiber or fat your meal will take longer to digest the
spike in protein synthesis in your body will last longer alright so now I’m
going to touch on some of the possible proposed health benefits of intermittent
fasting my interest in intermittent fasting was peaked a lot after seeing a new
paper in the New England Journal of Medicine that reviewed the role of
intermittent fasting in health now there have been a number of studies now that
might be suggesting a possible benefit of intermittent fasting with certain
metabolic conditions longevity and some other chronic diseases two of the
possible mechanisms that the paper talks about is metabolic switching and
improved stress resistance metabolic switching refers to how the body
switches from primarily using glucose for energy to ketones now most of the
time if you’re eating regularly your body will use glucose from carbohydrates
for energy or convert other nutrients into glucose to use that however if you
go for a prolonged period without eating something like 8 to 12 hours your body
starts producing ketones which it can also use for energy now the thing about
ketones is that they also signal other molecular pathways in your body which
may play a positive role in things like glucose regulation in diabetes or other
things like blood pressure the other main mechanism that the paper proposes
is stress resistance what this means is that if you fast at regular intervals
you’re repeatedly applying a stress to the cells
your body which may force them to adapt in a way that can reduce inflammation
over time or help them repair themselves which can impact certain chronic
diseases now Before we jump to conclusions I want to talk about some
caveats to the intermittent fasting research overall I’d say that this
branch of research is still fairly early and the evidence we have is not strong
enough for me to really push in term in fasting as a way to improve your health
the first thing that struck me when I was reading this review paper is that a
lot of benefits associated with intermittent fasting come from actual
caloric restriction itself and not actually the timing of your caloric
intake the next thing is that a lot of the studies that we talked about were
actually animal studies and were carried over a short term now usually if I were
to make a recommendation for a health intervention as a physician I would need
to see strong evidence first which usually involves large scale studies
involving human subjects over an extended period of time especially if
we’re talking about things like longevity now this is a big challenge
faced by diet research in general and it’s difficult for us to really say for
certain what exactly you should be eating for health okay so to quickly
summarize what we’ve talked about so far I’m gonna give you some of my
recommendations on intermittent fasting first of all if intermittent fasting helps
you to restrict your calories then it’s a good thing this applies to both weight
loss and for health however I do think that there is a possible disadvantage of
interment fasting to bodybuilders both in a cutting or bulking phase from a
muscle growth standpoint it makes theoretical sense that you want to have
protein available for your body to synthesize muscle for as many hours of
the day as possible and it’s very clear that if you’re bulking and trying to put
in a lot of calories you probably want to extend your eating window to make
sure you can fit that all in if your goal is fat loss however an intermittent
fasting helps you restrict your calories overall I think it’s still overall a
beneficial thing to do there is some research ongoing in terms of answering
that question as to whether intermittent fasting puts you at a disadvantage for
muscle growth but we’ll have to see what happens with that now in terms of the
health benefits of intrument fasting at this time I can’t make a strong
recommendation to do it however I’ve got to say that the research so far has been
pretty interesting and it’ll be something to keep an eye on so
ultimately I think whether you choose to do intermittent fasting or not is going
to be up to personal preference so if I do choose to implement this strategy how
should I do it first of all I would suggest starting off with the
conservative schedule something like 16 hours of fasting to an 8 hour feeding
window I’m a big proponent of sustainability and I think it’s
important to choose something that fits really well into your lifestyle next
from a body composition standpoint I would recommend spreading on your
protein as much as possible throughout your eating hours at least over three to
four meals lastly be consistent if you’re choosing to in term in fast stick
with the schedule and stay with it throughout that adjustment period and
see what happens afterwards and if it works for you that’s all for now guys if
you enjoyed this video make sure you like the video and leave me a comment
this really helps the channel and at this point I’m still answering virtually
all of my comments let me know if you want to see me cover other dieting
topics if you haven’t already, subscribe and we’ll see you next time



  • Ask Dr. Swole

    Check out my FREE science-based training programs here:


    I'm about to get back on my fasting I been doing it for about 6 years

  • Alf Staal

    Good one man 👍🏻

  • WAKE UP MOTHERF****R SMELLING Sniffing ammonia

    OKKKK butttt wooooooooooooo caresss

  • Rodrigo Garcia

    Great video man! Really enjoyed your opinion on this!

  • Just Some Guy without a Mustache

    You looked ripped bro

  • Michael Gad

    I have done IF for more than 1 year and all you have said is tottally true it helps without loss and a lot of health benefits but in you are looking to build muscle it's not you best option
    Also been followings you for a while how do you feel getting deeper into the cut?

  • ThatOneDude

    I've heard people saying during the fasting phase it will boost HGH because of the lack of insulin or something…? Idk. Any truth to HGH benefits?

  • J

    Hey Bill,

    Sorry this comment is so damn long, but I hope you read it…

    Your intros almost sound like you're whispering, but loudly. Like your roommate is asleep while you make videos at 3 AM. Instead, try to sound more engaging and active in in your speech, especially at the beginning.

    We don't need good bedside manner from a doctor here; It's YouTube. We need excitement, so: "heY GUYS, DOCTOR SWOLE, HERE!". Your voice pitch should go up and sound almost like you're taking a bite out of the sentence, toward the beginning. Put an emphasis on that first word in the sentence.

    Ask any successful healthcare recruiters or medical sales reps who try to network with you or your hospital about engaging speech in your videos.

    If that's just too weird or socially awkward, PLEASE ask me more in depth via PM what I mean. I'd be more than happy to help you educate more viewers.

    That said, keep up the good work, man. You have fantastic content. Just would love to see you spice up the delivery in order to gain more subscribers.

  • Driven By Vision

    Great video, insightfull

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